1. Field of the Invention
The present invention relates to an image projection apparatus.
2. Description of the Related Art
Conventionally, there is known an image projection apparatus provided with an image forming part to form an image with light emitted from a light source on the basis of image data from a personal computer (PC), video camera or the like, so that the image is projected and displayed on a screen or the like.
The image projector apparatus is provided with (i) a ballast board as an electrical power stabilizer for supplying stabilized electrical power (electrical current) to the light source with an AC (Alternate Current) voltage corresponding to fluctuation of the light source, and (ii) a PFC (Power Factor Correction) power source board as a power source board for supplying electrical power to a control board as a control unit for controlling the light source and the image forming part. For the electrical power stabilizer and the control unit, the PFC power source board boosts the AC voltage supplied from a power source cable.
The PFC power source board and the ballast board are provided with a great number of electrical elements such as a capacitor, a coil, a resistor and the like. These electrical elements generate heat to raise the temperature of boards. When the temperatures of the PFC power source board and the ballast board rise and become high temperatures, the operation performance and the durability may be lowered.
Japanese Patent Application Laid-open No. 2007-78924 discloses an image projection apparatus for blowing air to the PFC power source board to cool the PFC power source board by air.
However, a great number of electrical elements such as the capacitor, the coil and the resistor are mounted on the PFC power source board, as described above, and thus the area of the board itself is large and it is long in the flowing direction of the air. As a result, the air, which took heat from the PFC power source board on the upstream side and which temperature rose, flows on the downstream side of a flow path of the air that flows on the PFC power source board. A portion that is not sufficiently air-cooled thus may arise on the downstream side of the flow path of the air of the PFC power source board. The wind amount is raised by raising the rotation number of a fan and the like serving as an air blowing unit for blowing air to the PFC power source board or using a large fan so that the air of low temperature can also flow on the downstream side of the flow path of the air of the PFC power source board. However, if the rotation number of the air blowing unit is raised, the wind noise increases, the noise of the apparatus increases, and the power consumption increases.
Furthermore, an area deviated from the flow path of the air of the air blowing unit may arise on the PFC power source board having a large area and a portion that is not air-cooled may arise depending on the size and the arrangement position of the air blowing unit such as a fan. Thus, a large air blowing unit is required and the flow path of the air blown by the air blowing unit needs to be made large, in which case, the apparatus enlarges. Furthermore, the PFC power source board has a large area, as described above, and has a large volume since a great number of electrical elements are mounted thereon. Therefore, the PFC power source board cannot be arranged in an open space after each optical element of the image projection apparatus is arranged, and a space for arranging the PFC power source board needs to be prepared anew. The matters described for the PFC power source board also goes for the ballast board, and are the cause of enlargement of the apparatus.